Kapok Fiber Research Articles

Development and Characterization of Mikania, Kapok, Wool, Sugarcane, and Pineapple Fiber Reinforced Polyester Composite

ABSTRACTThis study utilizes plant‐derived fibers including Mikania, wool, kapok, sugarcane, and pineapple as strengthening additions to fabricated and tested reinforced polyester mixtures. This study aimed to examine the mechanical qualities and potential applications of these natural materials in boosting the effectiveness of polyester composites. The composites were formed by including natural fibers into a polyester base using a hand lay‐up preparation method. The finished samples received a complete assessment, covering tensile and impact testing as well as SEM analysis. The findings showed that incorporating natural materials like Mikania vines, wool, kapok fuzz, sugarcane fibers, and pineapple leaves had a notably positive effect on the mechanical features of the plastic composites. The tensile strength of the material combined pineapple was particularly high, achieving a maximum stress of 42.4822 N/mm2 and a maximum stretch of 4.27950%. Similarly, that same composite exhibited a maximum stretch of 3.75753% and a maximum stress of 77.4922 N/mm2 during the bending experiment. The substances exhibiting the strongest impact endurance, as determined by the impact assessment, included kapok, Mikania, wool, pineapple, and sugarcane. The kapok provided an impact toughness of 1.2 N m, which was somewhat elevated. This research offers a precious understanding of using natural fibers as strengthening additives in polyester composites, demonstrating their flexible perspective for many uses. The discoveries present hopeful possibilities for additional examination and progression in composite materials, consequently advancing the development of sustainable materials.

Multifunctional carbon nanotube arrays on kapok-derived carbon microtube composites for efficient electromagnetic wave absorption and Cu(II) removal

To cope with different environments of application, electromagnetic wave absorption (EWA) materials with multifunctionality have attracted a wide range of interests. And excessive heavy metal ions in aqueous solutions seriously affect people’s health and pose a major challenge to environmental safety. In this study, carbon microtube/carbon nanotube (CMT/CNT) composites were fabricated via carbonization and chemical vapor deposition (CVD) methods. The CNT wrapped with cobalt nanoparticles were grown in situ on the CMT which derived from kapok fiber. By varying the concentration of cobalt precursors, the EWA and Cu(II) adsorption performances of CMT/CNT can be efficiently tuned. Optimizing the cobalt content to 2 wt% resulted in a minimum reflection loss (RL) of −66.14 dB at a matching thickness of 1.91 mm, with an effective absorption bandwidth (EAB) of 5.35 GHz. The adsorption capacity of Cu(II) by the CMT/CNT composite can reach 102.01 mg/g when the initial Cu(II) concentration is 500 mg/L. This research not only shows great promise for applications in the field of EWA materials but also holds significant potential for heavy metal ion removal and as a catalyst carrier, among other areas.

Natural fibers as promising core materials of vacuum insulation panels

To reduce energy consumption in buildings, this paper investigates the feasibility of using natural fibers as cost-effective, environmentally sustainable core materials for vacuum insulation panels (VIPs). First, a comprehensive experimental study was conducted for 10 potential natural fiber candidates. The thermal conductivities of the 10 natural fiber mats at various vacuum pressures were measured; their compression and morphology properties were quantified. In addition, an analytical model was used to explore the major factors that influence the thermal conductivity of natural fibers as a function of internal air pressure. Results show that recycled cotton, kapok, and bamboo fibers are ideal candidates for VIP core materials; at <0.05 Pa, their thermal conductivities varied between 2 and 4 mW/(m⋅K). Furthermore, for some fibers, thermal conductivity was inversely proportional to fiber density. For the selection of fiber materials for VIP cores, the ideal fiber candidate has a small fiber diameter and a low fiber mat density. Based on thermal measurements, even though the internal air pressure of 5 Pa was enough to attain the minimum thermal conductivity, obtaining internal air pressure below 5 Pa is recommended for prolonged service life, considering small leaks of VIP package barrier films and potential off-gassing from fibers. The simulation results predicting the effective thermal conductivities matched the experimental results well. These findings indicate that natural fiber–based VIPs have the potential to be a sustainable, inexpensive alternative to the current technologies in building insulation materials.

An eco-friendly kapok fiber-supported liquid microextraction using natural deep eutectic solvent as extractant for convenient biological samples preparations: A proof-of-concept study

The use of natural materials and reagents is crucial for developing environmentally friendly methods. This study proposed an excellent green, convenient, cost-effective and rapid sample preparation method called kapok fiber-supported liquid-phase microextraction using natural deep eutectic solvent (KF-SLME-NADES). Natural kapok fiber and NADES were used as greener alternatives to conventional support medium and extractants. Low-toxic ethanol was employed as the desorption solvent. The extraction process was streamlined in a syringe form, allowing for simple pull-push operations. As a proof of concept, the developed methodology was utilized for extracting antidepressants from 3 mL of diluted biological fluids. The optimized KF-SLME-NADES conditions were obtained by single-factor experiments and Box-Behnken design as follows: 2 mg of kapok fiber, 13 μL of NADES composed of menthol and thymol in an equal molar ratio as the extractant, a sampling solution with a pH of 8.0, a desorption solution of 100 μL of ethanol, and four pull-push cycles for both extraction and elution. The validated method provided good linearity (0.05–5.00 μg/mL, R2 > 0.999) and possessed limits of quantification spanning from 0.025 to 0.048 μg/mL. Satisfied accuracies and precisions were obtained with relative recoveries ranging in 93.3–107.2% and intra- and inter-day RSD(%) being below 7.7%. The method greenness was found to be excellent by assessing five greenness evaluation metrics. The devised KF-SLME-NADES strategy provides a sustainable and effective method for bioanalysis.

Utilization of natural kapok and coconut fiber in thermally insulated sustainable concrete design.

Nowadays, when regenerable alternative green sources are attracting more caution under sustainability targets, kapok and coconut fibers, known as natural fibers, have come to the fore as a very significant raw material source. In this experimental study, compressive strength, thermal insulation, and pore structure characteristics of kapok fiber (KP)- and coconut fiber (CC)-incorporated concrete samples under different curing conditions were analyzed. For that purpose, randomly distributed fiber-incorporated concrete mixtures containing 0%, 0.5%, 1%, and 1.5% KP and CC fiber by the weight of cement were prepared and under H2O2 and NaClO curing conditions, the effects of KP and CC fiber inclusion on properties mentioned above of fiber-incorporated concrete samples were researched in detail. Experimental results depict that a maximum thermal conductivity coefficient decrease of 24.31% was detected at a content ratio of 1.5% by the reason of the pore modification effect of used natural fibers in the H2O2 curing group. Because of the remarkable pore modification effect of KP fiber incorporation into the cement matrix compared to the CC fiber inclusion cases, strong linear correlations revealing the insulation-strength mechanism could be detected for both H2O2 and NaClO curing cases. This work intends to promote sustainable development in the building industry by integrating natural fibers into concrete mixtures as an innovative design approach.

Automated kapok fiber-based pipette-tip solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for rapid and sensitive analysis of tyrosine kinase inhibitors in plasma

This study delineates the development of a novel automated pipette-tip solid-phase extraction (SPE) methodology, employing kapok fiber as a naturally efficient and cost-effective adsorbent for the selective extraction of eleven tyrosine kinase inhibitors (TKIs) from plasma. The uniqueness of this method lies in its assembly, where kapok fibers are ingeniously wrapped around a stainless-steel spring within the pipette tip, ensuring an obstruction-free central space for effortless solution aspiration and dispensation. This design significantly minimizes backpressure, enhancing operational efficiency and ensuring compatibility with pipettors, including the implementation of an electric pipettor to streamline the sample preparation process and facilitate automation. The method's analytical performance, rigorously validated through liquid chromatography-tandem mass spectrometry, exhibits outstanding linearity in ranges of 0.1/0.5–200 ng mL-1 (R² > 0.993), commendable accuracy (86.3%–114.8%), and consistent precision (3.4–11.3%), alongside remarkably low detection limits that span from 0.024 to 0.130 ng mL-1. The assembly of kapok fiber within the pipette tip, in this unique configuration, results in a practical, cost-effective, eco-friendly, and automated pipette-tip SPE method. This innovation signifies a significant advancement in bioanalytical methodologies, offering an efficient and sustainable approach for extracting analytes from complex biological samples. This process notably enhances both the sensitivity and selectivity of subsequent instrumental analyses.

Kapok/regenerated cellulose based carbon aerogel prepared at a low-temperature carbonization for oil/water separation

With the requirement of sustainable development in modern society, selective filtration and separation of oils and organic solvents from polluted wastewater is a critical and very important goal. Herein, a novel hydrophobic and oleophilic cellulose-based carbon aerogel composed of kapok fiber/regenerated cellulose was prepared at a low-temperature carbonization technique (300 ℃) directly using kapok and hardwood pulp as raw material, the N-methyl N-oxide monohydrate (NMMO·H2O) as a green cellulose solvent, and NH4H2PO4 (ADP) as a carbonization promotor, which is denoted as AX-KRCA(AX: A indicates the ADP used, x is the concentration of ADP solution (g/L)) The regenerated cellulose (RC) was converted from hardwood pulp via NMMO·H2O treatment, and further combined with kapok fiber to form a 3D porous structure. By adding ADP, AX-KRCA can be rapidly dehydrated into carbon at 300 ℃, which not only saves energy consumption but also retains the basic form of kapok fiber and regenerated cellulose, making it have excellent compressibility, elasticity, and fatigue resistance. The ultra-light porous AX-KRCA samples can be an efficient oil/water adsorbent, with an adsorption capacity from 98.0 to 232.1 g g−1 for various oils, and can maintain 87.3 % adsorption capacity after 20 cycles and 99.6 % separation efficiency after 5 times of filtration.

Bio-templated micromotors for simultaneous adsorption and degradation of microplastics

Microplastic contamination has increasingly become a focus of public attention due to its ubiquity on earth. As the appearance of microplastics in the human body has raised great concerns about their effects on human health, it is imperative to develop efficient technologies to remove microplastics. In this work, taking advantage of the hollow structure of kapok fibers and low-cost MnO2 catalyst, a tubular self-driven micromotor was synthesized for simultaneous adsorption and degradation of microplastics. Functionalization with polydopamine endowed the micromotors with the ability of on-the-fly capture of microplastics. Attributed to the enhanced diffusion caused by the self-propulsion, the propelled micromotors exhibited an adsorption efficiency 3.41 times that of static micromotors, achieving a removal ratio of 73.57 % in 1 mg/mL polystyrene microspheres dispersion in 30 min without external stirring, which poses a prospective approach for in-situ removal of microplastics. In addition, coupling with photocatalytic CdS, the formed CdS/PDA heterojunction could generate photo-induced charge carriers, which together with the active species produced through the Fenton-like processes contributed to the degradation of microplastics. This work proposed a new platform for the simultaneous adsorption and degradation of microplastics and may provide implications for the removal of microplastics in the environment.

BioTemplated Fe3+-Doped g-C3N4 Heterojunction Micromotors for the Degradation of Tetracycline through the Photo-Fenton Reaction

The excessive discharge of antibiotics into aquatic systems is a major issue in many countries worldwide and poses a threat to human health and the sustainable development of society. Hence, developing efficient treatment methods and purification technologies to degrade antibiotics is essential. Herein, we present the synthesis of low-cost, self-propelled tubular Fe3+-incorporated graphitic carbon nitride (g-C3N4-Fe@KF) micromotors using kapok fibers (KFs) as templates and their application as photo-catalysts for the photo-Fenton degradation of tetracycline (TC) under visible-light irradiation. The g-C3N4-Fe@KF micromotors moved rapidly when being propelled by oxygen bubbles generated in a hydrogen peroxide (H2O2) solution as a result of a photo-assisted Fenton reaction. The motion behavior of the g-C3N4-Fe@KF micromotors was dependent on the concentration of H2O2 and the length of the micromotors. The propulsion mechanism was discussed in detail. The micromotors efficiently degraded antibiotics via the photo-Fenton process. Photo-Fenton degradation efficiency was attributed to the synergistic effects of the doped Fe3+ and g-C3N4 under visible-light irradiation and self-propulsion of the micromotors. In addition, the micromotors possessed good reusability, thereby efficiently realizing multiple cycles of degradation. The current work offers an avenue for the design of micromotors, using inexpensive approaches, for various potential environmental applications.

Modification on Fiber from Alkali Treatment and AESO Coating to Enhance UV-Light and Water Absorption Resistance in Kapok Fiber Reinforced Polyester Composites

ABSTRACT Environmental contamination poses a significant threat to the integrity of materials, including metals and composites. Addressing the degradation of natural fiber-reinforced polymer composites necessitates effective management strategies, particularly in mitigating UV and water-induced deterioration. This study explores the efficacy of Acrylated Epoxidized Soybean Oil (AESO) coating treatment following alkali treatment as a potential solution. Alkali treatment of Kapok fiber (KF) combined with polymer coating yielded composites exhibiting superior mechanical properties, particularly in tensile and flexural strength, following a 30-day aging period. Remarkably, the application of alkali and coating treatments led to a substantial enhancement in the mechanical strength of polyester composites, with the highest tensile strength recorded at 96.04 MPa. This represented a notable increase of 31.97% compared to untreated KF specimens. The observed enhancement in composite performance underscores the critical role of interfacial adhesion between fibers and the matrix, particularly under conditions of UV exposure and water immersion. Importantly, the study demonstrates that alkali treatment and polymer coating effectively mitigate degradation in Natural Fiber-Reinforced Polymer Composites, thereby offering promising avenues for enhancing their durability and longevity.

Modification of biodegradable thermoplastic cassava starch/kapok fiber incorporated by tartaric acid and processed by compression molding technique

Thermoplastic starch has been attracted due to its availability, biodegradability, and processability. However, its poor tensile properties, high hydrophilicity and lack of antibacterial activity are still the major concerns for many applications. In current study, several thermoplastic cassava starch samples (THPCS), reinforced with kapok (KP) fibers and modified by varying levels of tartaric acid (TA), a natural organic acid, were prepared to enhance their limitations. All samples were mixed and shaped using an internal mixer and a compression molding machine, respectively. The modified THPCS samples were characterized using analytical techniques such as FTIR, SEM and TGA. Morphology, water uptake, mechanical properties, biodegradability, and antimicrobial performance of various samples were also evaluated. IR peak positions of O–H stretching as well as O–H bending were clearly observed for shifting to lower wavenumbers with the addition of KP fibers or KP fibers/TA, indicating of new H-bond formation. In addition, the use of KP fibers caused the enhancement of mechanical strength and thermal properties including the reduction of water uptake. Moreover, THPCS/KP fiber sample modified by TA presented surface smoothness, good biodegradability, and antibacterial performance against both Staphylococcus aureus and Escherichia coli.

Functionalising kapok fibre with lignin to enhance the structural and thermal performance of vacuum insulation panels

Kapok fibre has the advantage of low density, low porosity and low thermal conductivity, which make it an excellent substitute for fumed silica and environmentally-unfriendly synthetic polymers as core material of vacuum insulation panels (VIP). However, kapok fibre is hydrophobic, consequently, kapok fibre core materials made by conventional wet forming with weakly-bound fibres and large voids that shorten their service life. Lignin is a natural and sustainable material that has good hydrophilicity and small particle size to form nano-porous networks. Therefore, we herein present the incorporation of lignin in kapok fibre to generate a composite core material with hierarchical porous structure. Lignin functionalises the kapok fibre surface to make it hydrophilic and dispersible in water. Simultaneously, lignin enhances the mechanical properties and service life of core material by transforming its internal microstructure. The effective thermal conductivity of prepared VIP is below 6.00 mW/(m∙K), and after 28 days of accelerated ageing test without desiccant or getter, the effective thermal conductivity increases less than 5.00 mW/(m∙K). Interestingly, the addition of lignin also reduces radiative heat transfer in the VIP. So, lignin addition enables high-performance VIP to be produced. Moreover, as a natural material, kapok fibre is low-cost, environmentally-friendly, sustainable, and energy-efficient.

Effect of Loading of Kapok Fiber with Epoxy on Mechanical and Electrical Properties of Its Composites

Effect of Loading of Kapok Fiber with Epoxy on Mechanical and Electrical Properties of Its Composites

Mechanical properties of web kapok/fiberglass-epoxy hybrid composites for marine structures

Abstract This study investigates the mechanical properties of hybrid composites composed of web kapok fibers and fiberglass reinforced with epoxy for potential application in the marine industry. The web kapok fibers were carefully processed using a carding technique to ensure better alignment and consistency. Various composite configurations were produced, and extensive mechanical testing was conducted, including flexural, tensile, and impact tests. The results revealed that the presence of two web kapok fiber layers within the composite significantly increased flexural strength and flexural modulus compared to pure fiberglass laminates. However, a single layer of web kapok fabrics exhibited the highest tensile strength, although it decreased with additional layers. The impact strength of these hybrid composites also showed promising results, especially when compared to raw fiberglass composites. Moreover, these composites exhibited improved resistance to water absorption and corrosion, making them potentially suitable for marine applications. This research highlights the potential of web kapok/fiberglass hybrid composites as an eco-friendly alternative for marine engineering, with implications for reduced environmental impact and sustainable technology in the industry.

A novel cost-effective kapok fibers and regenerated cellulose-based carbon aerogel for continuous oil/water separation

The development of cost-effective, environmentally friendly, and reusable superabsorbent materials for removing oil spills from water presents significant challenges. Herein, a novel, cost-effective, environmentally friendly, and reusable carbon aerogel (KRxCA) was synthesized by combining kapok fibers (KF) with hardwood pulp regenerated cellulose, dissolving in a mixture of N-methyl morpholine-N-oxide monohydrate (NMMO) and deep eutectic solvent (DES), which is named co-solvent DNS. This carbon aerogel presents remarkable compressibility, elasticity, and fatigue resistance, maintaining maximum stress after 100 cycles at 50 % strain due to its three-dimensional network of carbonized hollow tubular KF fixed by carbonized regenerated cellulose. The water contact angle (144.7°) indicates the excellent hydrophobicity of the KR10CA, demonstrating the potential for efficient oil/water separation. The resulting ultra-light (3.78 mg cm−3) and high porous (98.9 %) KR10CA exhibits exceptional oil sorption capacity (137.5–371.7 g⋅g−1) and retains 89.3 % of its sorption capacity after ten extrusion cycles. Additionally, as a filter membrane, the KR10CA effectively separates n-hexane from water with a high flux rate (21972.7 L m-2h−1). Therefore, the carbon aerogel derived from renewable resources presents itself as a cost-effective and environmentally friendly oil/water separator for practical application.

The Synergistic Effect of Nitrogen-Doped Carbonized Kapok Fiber to Amorphous/Nanocrystalline Fe85 SiAl6 Cr8 for Broad Effective Absorption Bandwidth Microwave Absorber

With the increasing quantity of intelligent and portable electric devices, a broad effective absorption bandwidth (EAB) microwave absorber (MWA) is required for shielding microwave (MW) interference. An MWA with a magnetic-dielectric synergistic effect is necessary for broadening the EAB of it. The amorphous/nanocrystalline [Formula: see text]SiAl6Cr8 (FSAC) is a nanolevel high magnetic loss MWA, and the introduction of medium dielectric loss MWA nitrogen-doped carbonized kapok fiber (NCKF) with an appropriate proportion improved the impedance match and damping ability of the composite and broadened the EAB. The results revealed that the minimum reflection loss ([Formula: see text] of FSAC/NCKF was -22.5 dB at 16.8[Formula: see text]GHz with a thickness of 1.20[Formula: see text]mm, and the EAB was 4.91[Formula: see text]GHz with a thickness of 1.30[Formula: see text]mm. Besides, the EAB moved to the low-frequency range when the thickness increased. Meanwhile, the RL of the simulation and the experiment were remarkably similar. The strategy offers an approach for developing a MWA with broad EAB.

A hollow carbonized kapok fiber/nano CoFe2O4 composite for broad bandwidth and enhanced microwave absorber

The development of intelligent and portable electrics necessitates the creation of an enhanced electromagnetic absorption and broad bandwidth microwave absorber. The synthesis of nano cobalt ferrite (CoFe2O4; CFO) combined with hollow carbonized kapok fiber by the Sol-Gel method and annealing process is a promising approach. The microwave absorption of carbonized kapok fiber/CFO was enhanced, and the bandwidth broadened due to the dielectric loss microwave absorber carbonized kapok fiber synergizing with the magnetic loss microwave absorber CFO. The results demonstrated that the minimal reflection loss of carbonized kapok fiber/CFO-6 was −52.2 dB at 8.56 GHz, with a thickness of 3.37 mm, and the broadest effective absorbing bandwidth was 6.2 GHz, with a thickness of 2.31 mm. The simulation results, which were obtained using the CST MWS software, exhibited a high degree of agreement with those obtained from the experimental measurements. The strategy offers a prospective method for the preparation of enhanced absorption and broad bandwidth microwave absorbers.

Manufacturing Biodegradable Bioplastics from A Mixture of Starch and Kapok Fibers with Variations of Chitosan and Glycerol

Manufacturing Biodegradable Bioplastics from A Mixture of Starch and Kapok Fibers with Variations of Chitosan and Glycerol

Synthesis of Co@CoO/C by micro-tube method and their electrochemical performances

Lithium-ion batteries (LIBs) are promising secondary batteries that are widely used in portable electronic devices, electric vehicles and smart grids. The design and synthesis of high-performance electrode materials play a crucial role in achieving lithium-ion batteries with high energy density, prolonged cycle life, and superior safety. CoO has attracted significant attention as a negative electrode material for lithium-ion batteries due to its high theoretical capacity and abundant resources. However, its limited conductivity and suboptimal cycling performance impede its potential applications. The study proposes a novel micro-tube reaction method for the synthesis of Co@CoO/C, utilizing Kapok fiber as a template with a special hollow structure. The microstructure and composition of the samples were characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After conducting electrochemical performance tests, it was discovered that at a current density of 100 mA/g and within the range of 0.01–3.0 V for 50 charge and discharge cycles. Co@CoO/C composite negative electrode exhibits a reversible lithium insertion specific capacity of 499.8 mAh/g and keep a discharge capacity retention rate of 97.6 %. The greatly improved lithium storage and stability performance of Co@CoO/C composite anode is mainly attributed to the synergistic effect between Co@CoO nanoparticles and the kapok carbon microtubule structure.

Natural kapok fiber as a green and efficient adsorbent for in-syringe solid-phase extraction in the determination of antidepressants in biofluids

Effective antidepressant monitoring is crucial for safe treatment, with liquid chromatography being the primary detection method. Due to the complexity of biofluids, meticulous sample preparation is vital to remove interferences and concentrate analytes. In this study, a novel solid-phase extraction method utilizing unprocessed kapok fiber (KF) as an eco-friendly and efficient sorbent, ingeniously incorporated within an in-syringe device for the extraction of antidepressants from biofluids was introduced. The extraction process displayed several advantages, including simplicity and rapidity (less than 3 min with minimal manual intervention), as well as the potential for automation, which represents significant advancements in sample preparation techniques. The method demonstrated excellent analytical performance when coupled with high-performance liquid chromatography-ultraviolet detection, achieving good linearity (R2 ≥ 0.991), excellent relative recovery (92.6–107.5 %), high precision in intraday and interday analyses (RSDs within 0.8–6.0 % and 1.2–7.9 %, respectively), and good sensitivity with limits of quantification between 5–10 ng/mL. Notably, given the use of a renewable and biodegradable material with KF, and a low-toxicity desorption solvent with ethanol, the developed method stands out for its environmental sustainability, aligning with green analytical chemistry principles. Its application to real biological samples validates its efficacy as a rapid and reliable tool for clinical and forensic monitoring of antidepressants. Moreover, the low cost of this method facilitated by the economical nature of KF and the reusability of syringes further enhances its practicability. This study presents a unique approach by employing natural and renewable KF as adsorbents, thereby eliminating the need for complex material synthesis and making a pioneering contribution to the field of analytical chemistry for drug analysis in complex matrices.